diff --git a/CMakeLists.txt b/CMakeLists.txt
index 93863d9e1..193a33b2f 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -92,8 +92,25 @@ else ()
   endif ()
 endif ()
 
+
 project(freetype)
 
+
+# Disallow in-source builds
+if ("${PROJECT_BINARY_DIR}" STREQUAL "${PROJECT_SOURCE_DIR}")
+  message(FATAL_ERROR
+    "
+In-source builds are not permitted!  Make a separate folder for"
+    " building, e.g.,"
+    "
+  mkdir build; cd build; cmake .."
+    "
+Before that, remove the files created by this failed run with"
+    "
+  rm -rf CMakeCache.txt CMakeFiles")
+endif ()
+
+
 if (BUILD_FRAMEWORK)
   if (NOT "${CMAKE_GENERATOR}" STREQUAL "Xcode")
     message(FATAL_ERROR
diff --git a/ChangeLog b/ChangeLog
index 4611972bd..d19b61859 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+2015-06-28  Werner Lemberg  <wl@gnu.org>
+
+	* CMakeLists.txt: Disallow in-source builds.
+
 2015-06-27  Werner Lemberg  <wl@gnu.org>
 
 	* src/tools/docmaker/utils.py (check_output): Add missing `\n'.